Hi Diane, this looks like a hood liner, which is the shell of the hood surrounded by custom cabinetry, so whoever makes your cabinetry would make the hood surround. Regarding use with a 6 burner Wolf, I would recomend the Wolf pro hood liner (http://www.subzero-wolf.com/oven/range-hood/hood-liner), in either 36", or 42" for a greater capture area, with at least a 900 cfm motor.

It looks like sateen white.

These look like an Absolute Black granite or a soft black solid surface. Really nice in the space.

Island seating should be a convenience and not a necessity. If you like to entertain or have the kids watch you as you prepare meals, island seating can be convenient. Since you say you have a large dining table adjacent to this area - you may not utilize the seating.

I would keep your mind open. Do without at the beginning, and see how your family enjoys. You may find in the future it helpful, or you may enjoy your island without it! It's your home, do what fits your family's lifestyle best! :)

Honestly, an overhang does change the look of an island quite a bit - it takes it from feeling like a furniture piece to something else. That said, if you do legs on the other end, and an apron under the overhang it will help bring back the furniture look. The picture in the link below shows a wood apron below the countertop.
http://www.houzz.com/photos/42045/Marielle-traditional-kitchen-other-metros

Thank so much. I didn't about aprons- great idea!

Schoolhouse Electric has some that are quite similar:

http://www.schoolhouseelectric.com/fixtures-type.asp?type=Pendant